The section 144 has been implemented for 15 days in Quetta with the aim to control the spread of deadly virus which was rapidly spread in Quetta district.
The decision came two days before Spain was to resume use of the AstraZeneca vaccine after the EU's drug regulator deemed the jab "safe and effective".
The minister said an investigation was underway to determine what led to the shortage of oxygen in the state-run hospital and if it was the cause of the deaths.
They said the evidence of the drug's "profound efficacy" meant hospitalisation for early treatment of adults at high risk from Covid-19 could be stopped.
The health ministry also reported 296 new coronavirus deaths in hospitals, from 436 on Tuesday, bringing the cumulative death toll to 80,443. Total cases now stand at 3.38 million.
As in other countries, Mexico has begun rolling out its vaccination program, but at the same time the ranks of infected people swells, some days by the tens of thousands.